Collaborative Research: Quantifying the Role of Interfaces in Liquid Separation Membranes based on Carbon Molecular Sieves

燃料、化学品、药品、水和许多其他日用消费品都是从自然资源中经过一系列精炼过程生产出来的。然后必须从原料中分离和纯化所需的化合物，这是一个重大的技术挑战。液相分离尤其具有挑战性，因此对环境和能源的影响很大，而且还在不断增长。例如，每年仅在采出水应用中就处理了超过1万亿加仑的含有机水。这一数量预计将随着全球能源生产的增加而增加，并继续包括生物精炼厂和生化工厂的贡献。碳分子筛（CMS）是一种刚性固体材料，其孔的大小与液体化合物的分子相当。CMS材料可以作为筛子，以一种节能的方式分离和纯化液体化合物，以应对这些新的挑战。然而，CMS在分离中的性能可能不太理想。CMS分离性能的限制通常归因于与CMS表面和界面上的分子运输有关的各种影响。在本研究项目中，研究人员将结合先进的实验技术来测量和了解不同相关长度尺度下CMS材料内液体分子的运动。在这个项目中创造的基础知识将使CMS材料的设计用于目标化学分离。该研究项目与一项教育和推广计划相结合，该计划的重点是提高代表性不足的学生对STEM的兴趣并留住他们。本研究的目的是量化和理解独立式CMS膜和将CMS颗粒分散在聚合物中形成的杂交CMS膜所表现出的与期望分离性能的偏差。这些偏差通常归因于与CMS表面和界面上的小分子运输有关的各种非理想效应。研究人员将结合先进的扩散核磁共振（NMR）光谱和宏观输运测量来量化界面上的输运，包括通过CMS表面屏障和混合膜中聚合物-CMS界面上的低密度缺陷的输运。这些发现将用于创建可验证的结构-输运关系，从而导致基于cms的液体分离膜的新设计原则。该项目将开发重要的基础知识，了解基于cms的膜中界面在1微米以下和1微米以上的整个相关长度范围内的液体传输中的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Fuels, chemicals, pharmaceuticals, water, and many other daily-use consumer products are manufactured from natural resources by a series of refining processes. The desired chemical compounds must then be separated and purified from the raw materials, which represents a significant technological challenge. Liquid-phase separations are particularly challenging and, as a result, have a large environmental and energy footprint that continues to grow. For instance, more than 1 trillion gallons of organic-loaded water are treated each year in produced water applications alone. This volume is expected to increase along with global energy production and continues to include growing contributions from biorefineries and biochemical plants. Carbon molecular sieves (CMS) are rigid solid materials with holes that are comparable in size to molecules of liquid compounds. The CMS materials can be used as sieves to separate and purify liquid compounds in an energy-efficient way to address these new challenges. However, the performance of CMS in separations can be less than desirable. CMS separation performance limitations are often attributed to various effects related to molecular transport at the CMS surfaces and interfaces. In this research project, the investigators will combine advanced experimental techniques to measure and understand the motion of liquid molecules within the CMS materials at different relevant length scales. The fundamental knowledge created during this project will enable the design of CMS materials for targeted chemical separations. The research program is integrated with an educational and outreach plan that focuses on increasing interest among and retention of underrepresented students in STEM. The goal of this research is to quantify and understand deviations from the desired separation performance often exhibited by freestanding CMS membranes and hybrid CMS membranes formed by dispersing CMS particles in a polymer. These deviations are often attributed to various non-ideal effects related to small molecule transport at CMS surfaces and interfaces. The investigators will combine advanced diffusion nuclear magnetic resonance (NMR) spectroscopy and macroscopic transport measurements to quantify transport at interfaces, including transport through CMS surface barriers and along low-density defects at the polymer-CMS interfaces in hybrid membranes. These findings will be used to create verifiable structure-transport relations, leading to new design principles of CMS-based membranes for liquid separations. The project will develop important fundamental knowledge of the role of interfaces in CMS-based membranes on liquid transport across an entire range of relevant length scales below and above one micrometer.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.